Random access in dynamic and shared spectrums

Abstract

Systems and methods for using a communication system in a spectrum are provided. For example, a random access or RACH procedure may be performed where the random access or RACH procedure may be configured to reduce secondary interference and/or to be used in a pixel-based environment. The random access or RACH procedure may include selecting a RACH preamble; sending a RACH preamble and/or format information; determining a transmission power of the RACH preamble and/or the format information; determining a random access radio network temporary identifier (RA-RNTI) and preamble ID associated with the RACH preamble; and/or selecting a physical RACH (PRACH).

What is claimed: 
     
       1. A method for a wireless transmit/receive unit (WTRU) to perform random access, the method comprising:
 determining a value for a random access channel (RACH) factor; 
 determining a value of a preamble parameter based on the determined value for the RACH factor; and 
 sending at least one RACH preamble based on the determined value of the preamble parameter. 
 
     
     
       2. The method for  claim 1 , wherein the RACH factor comprises a remaining time of a RACH attempt, and the preamble parameter is a number of repetitions for sending the at least one RACH preamble. 
     
     
       3. The method for  claim 1 , wherein the random access is performed on a plurality of cells comprising a first cell and a second cell, and the method further comprises:
 determining to use the at least one RACH preamble for the first cell and the second cell; and 
 sending the determined at least one RACH preamble on the first cell and the second cell. 
 
     
     
       4. The method for  claim 1 , wherein the random access is performed on a plurality of cells comprising a first cell and a second cell, and the method further comprises:
 determining to use a first RACH preamble for the first cell and a second RACH preamble for the second cell; and 
 sending the determined first RACH preamble on the first cell and the determined second RACH preamble on the second cell. 
 
     
     
       5. The method for  claim 2 , wherein the remaining time of the RACH attempt is calculated based on a duration of a RACH subframe and a listen before talk duration. 
     
     
       6. The method for  claim 2 , wherein the number of repetitions for sending the at least one RACH preamble is determined further based on a size of the at least one RACH preamble. 
     
     
       7. The method for  claim 2 , wherein the RACH factor is whether an indication of collisions is received by the WTRU, and the preamble parameter is a timing for sending the at least one RACH preamble, wherein based on receiving the indication of collisions, the timing for sending the at least one RACH preamble is randomly determined. 
     
     
       8. The method for  claim 5 , the method further comprising:
 determining whether a secondary user is present in the RACH subframe during the listen before talk duration, wherein the sending at least one RACH preamble is performed upon a determination that a secondary user is absent in the RACH subframe. 
 
     
     
       9. A wireless transmit/receive unit (WTRU) configured to perform random access, comprising:
 a processor; and 
 a memory in communication with the processor and storing instructions that, when executed by the processor, cause the WTRU to:
 determine a value for a random access channel (RACH) factor; 
 determine a value of a preamble parameter based on the determined value for the RACH factor; and 
 send at least one RACH preamble based on the determined value of the preamble parameter. 
 
 
     
     
       10. The WTRU for  claim 9 , wherein the RACH factor comprises a remaining time of a RACH attempt, and the preamble parameter is a number of repetitions for sending the at least one RACH preamble. 
     
     
       11. The WTRU for  claim 9 , wherein the random access is performed on a plurality of cells comprising a first cell and a second cell, and the processor is further configured to:
 determine to use the at least one RACH preamble for the first cell and the second cell; and 
 send the determined at least one RACH preamble on the first cell and the second cell. 
 
     
     
       12. The WTRU for  claim 9 , wherein the random access is performed on a plurality of cells comprising a first cell and a second cell, and the processor is further configured to:
 determine to use a first RACH preamble for the first cell and a second RACH preamble for the second cell; and 
 send the determined first RACH preamble on the first cell and the determined second RACH preamble on the second cell. 
 
     
     
       13. The WTRU for  claim 10 , wherein the remaining time of the RACH attempt is calculated based on a duration of a RACH subframe and a listen before talk duration. 
     
     
       14. The WTRU for  claim 10 , wherein the number of repetitions for sending the at least one RACH preamble is determined further based on a size of the at least one RACH preamble. 
     
     
       15. The WTRU for  claim 10 , wherein the RACH factor is whether an indication of collisions is received by the WTRU, and the preamble parameter is a timing for sending the at least one RACH preamble, wherein based on receiving the indication of collisions, the timing for sending the at least one RACH preamble is randomly determined. 
     
     
       16. The WTRU for  claim 13 , wherein the processor is further configured to:
 determine whether a secondary user is present in the RACH subframe during the listen before talk duration, wherein the sending at least one RACH preamble is performed upon a determination that a secondary user is absent in the RACH subframe.